Rainy weather is good news for Memorial Day plans. Seem contradictory? TVA explains

Despite severe drought conditions that gripped East Tennessee last fall and winter, Memorial Day boating plans should be unaffected thanks to an abnormally rainy May, the Tennessee Valley Authority said.

The Knoxville area, which typically receives 2.75 inches of rain in May, had already received 5.15 inches by May 20, according to the National Weather Service. All that rain means Tennessee lakes are sitting at their normal summer water level and, in some cases, at a higher than normal level as summer approaches.

Water levels at reservoirs along the Tennessee River and its tributaries – which you probably know as your favorite lakes for summertime fun – depend mostly on rainfall and runoff. But TVA can control water levels either by releasing or holding water back at its 49 dams.

It looked like Tennessee's lakes would not make it to their summer levels, which TVA calls "summer pool," before the state received between 3.5 and 5 inches of rain during storms in early May. If the lakes had not reached summer water levels, boaters and skiers would have faced greater risks from rocks beneath the surface.

Yay for rising lake levels, but excess water can be dangerous, too

The Tennessee river watershed has experienced 222% more rain and 153% more runoff than a normal May, TVA spokesperson Scott Brooks said via email, and excess water comes with its own safety risks.

TVA will let water rush through many of its dams, and runoff could wash debris into lakes. Because of this, Brooks said, people should use "extreme caution" over the next several weeks.

"Obey all signage and warnings, especially near or below any dam that is spilling," he said. "Avoid areas around the dams while we’re spilling water. Watch for floating hazards and debris, even in areas you are familiar with."

TVA typically begins holding water in its reservoirs in March in order to reach safe summer levels by June 1. Those levels came early enough this year that most lakes will be at summer levels by Memorial Day on May 27.

Tributary reservoirs in East Tennessee – like Cherokee, Douglas and Norris lakes – will be particularly full as summer starts, Brooks said. Water levels in lakes along the main river, like Fort Loudon Lake and Watts Bar Lake, do not fluctuate as much since boats must be able to navigate along the river.

Know Your Knox: Is downtown Knoxville on Fort Loudoun Lake or the Tennessee River?

River Forecast Center helps prevent floods, promote fun

From its River Forecast Center in Knoxville, TVA tracks water levels on both sides of each of its dams. Some of those dams date back to the federal power provider's founding in 1933.

TVA manages all 652 miles of the Tennessee River from Knoxville to Paducah, Kentucky, including 43 lakes. Beyond recreation, TVA manages flood prevention, hydroelectric power production, water supply, water quality and navigation.

"We like to generate as much power with every drop of rainfall we can so we don’t have to use other, more expensive forms of fuel as much, like coal and natural gas," Brooks said.

Before TVA controlled flows along the Tennessee River, it flooded all the time. Now the power provider prevents up to $246 million in flood-related damages per year.

Between June 1 and Labor Day, TVA keeps water levels high for recreation, limiting the amount it lets through its dams. It begins drawing the level down as summer ends to prepare for winter and produce more carbon-free power at its dams.

"We do need normal rainfall to maintain that elevation throughout the summer, so we'll be using the minimum amount of water we need to maintain the downstream commitments and the water quality ... to make sure we can maintain and hold on to reservoir levels," river forecast manager Darrell Guinn said in an interview provided by TVA.

TVA's dams can produce up to 3,538 megawatts of power, enough for about 2 million homes and 9% of the utility's total power generation.

In order to meet summer power demand peaks when the temperature stays above 90 degrees and customers run their AC full blast, TVA is able to produce 32,139 megawatts. About 55% of that power comes from carbon-free sources, including 42% from nuclear plants. Natural gas, oil and coal account for 45% of TVA power.

Keep up with East Tennessee lake levels through TVA app

TVA posts hourly information about lake water levels at TVA.com and on its Lake Info app, which is free to download.

The app tracks real-time water levels on both sides of TVA's dams, as well as how much water is spilling through the dams each hour. It also provides daily water release schedules, the history of TVA lakes and maps of dams and reservoirs.

Across the entire Tennessee River watershed, TVA is responsible for:

• 11,000 miles of shoreline

• 40,000 miles of streams and rivers

• 293,000 acres of public land

• 650,000 acres of water

TVA serves 10 million power customers across its seven-state region.

Daniel Dassow is a growth and development reporter focused on technology and energy. Phone 423-637-0878. Email daniel.dassow@knoxnews.com.

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This article originally appeared on Knoxville News Sentinel: TVA: East Tennessee lake levels safe for Memorial Day thanks to rain